BACTERIAL MENINGITIS Changing Spectrum of Disease

1. BACTERIAL MENINGITISChanging Spectrum of Disease Gary R. Strange, MD, MA, FACEP Professor and Head Department of Emergency Medicine University of Illinois at Chicago

2. EPIDEMIOLOGYNeonatal • 0.6 – 1.3 cases/1000 live births • Etiology • Group B Streptococcus • Escherichia coli • Listeria monocytogenes • Incidence essentially unchanged in the past 20 years

3. EPIDEMIOLOGYInfant and Childhood • 1990: children between 2 months and 5 years of age accounted for ¾ of all cases • 67% due to Haemophilus influenzae type b • 25% due to Streptococcus pneumoniae • 10% due to Neisseria meningitidis • 2002: children 2 mos – 5 yrs are < ½ of cases • Streptococcus pneumoniae is the most common cause between 2 mos and 2 years of age • Decreasing after introduction of heptavalent vaccine • Neisseria meningitidis is the most common offender in the 2 – 18 year age group

4. EPIDEMIOLOGY • Now predominantly a disease of adolescents and young adults • College students living in dormitories • Military recruits

5. EPIDEMIOLOGY • Conjugate polysaccharide Haemophilus influenzae type b vaccine introduced in 1991 • Heptavalent pneumococcal conjugate vaccine introduced in 2000 • Covers 80% of invasive serotypes • Projected to prevent 12,000 cases/year

6. PATHOPHYSIOLOGY • Hematogenous spread • blood to subarachnoid space • Mechanical disruption • Fracture of the base of the skull • Direct extension from ear, mastoid air cells, sinuses, orbit or other adjacent structure

7. PATHOPHYSIOLOGY • Pathologic changes of meningitis • Directly due to infection • Indirectly due to infection via the response of the immune system to infection

8. PRESENTATION • Classic Signs • Headache • Photophobia • Stiff neck • Change in mental status • Bulging fontanelle • Nausea • Vomiting

9. PRESENTATION • Signs of Meningeal Irritation • Brudzinski Sign: when the inflamed meninges are stretched with neck flexion, the hips and knees involuntarily flex. • Kernig Sign: when the hip is flexed to 900 , examiner is unable to passively extend the leg fully. • Children with meningeal irritation often resist walking or being carried • Absence does not rule out intracranial infection • Not useful in neonates and young infants

10. PRESENTATIONNeonates and Young Infants • Less obvious signs and symptoms • Poor Feeding • Irritability • Inconsolability • Listlessness

11. PRESENTATIONCourse of Disease • Insidious (90%) • High likelihood of early presentation with non-specific illness • Typical of pneumococcal illness • Fulminant (10%) • Typical of meningococcal illness • May progress rapidly to petechiae, purpura fulminans, cardiovascular collapse

12. DIFFERENTIAL DIAGNOSISEarly Stage of Disease • Gastroenteritis • Upper respiratory infection • Pneumonia • Otitis media • Viral syndrome

13. DIFFERENTIAL DIAGNOSISLater Stage of Disease • Encephalitis • Subarachnoid/Subdural Hemorrhage • Traumatic (Abuse or Unintentional) • Spontaneous • Cerebral Abscess • Reye’s Syndrome • Toxic Ingestions • Seizure Disorders • DKA or other altered metabolic states • Hypothyroidism • Intussusception

14. MANAGEMENTUnstable Patients • Always assure stability of vital functions before attempting diagnostic procedures • Withhold lumbar puncture until after stabilization and antibiotic administration • Shock: rapid intravenous or intraosseous infusion of crystalloid solution in 20 mL/kg aliquots until stable • Limit fluids to maintenance rate after stabilized • Fluid overload can lead to worsening of cerebral edema

15. MANAGEMENTIncreased Intracranial Pressure • Recognition: worsening mental status, papilledema, bulging fontanelle, widening of sutures • Treatment • Elevate head of bed to 300 • Controlled ventilation to keep PCO2 between 30 and 35 mmHg • Mannitol, 0.25 – 1 g/kg • Furosemide, 1 mg/kg

16. MANAGEMENT Stable Patients • Phlebotomy for diagnostic studies • Complete Blood Count • Serum Electrolytes • Blood Glucose • Renal Functions • Blood Culture • Lumbar Puncture for Cerebrospinal Fluid Analysis

17. CSF ANALYSISNormal Values for an Infant/Child • Cell count: 0-7 wbc/mm3 (0% PMNs) • Glucose: 40-80 mg/dL (> 50% of Blood Sugar) • Protein: 5-40 mg/dL

18. CSF ANALYSISInterpretation • Viral Etiology • Low wbc count • Predominantly mononuclear cell type • Normal glucose • Normal protein • Bacterial Etiology • Elevated wbc count • Predominantly polymorphonuclear leukocyts • Low glucose • High protein

19. INITIAL ANTIBIOTIC TREATMENTNeonates • Ampicillin, 100 mg/kg AND • Aminoglycoside • Gentamicin, 2.5 mg/kg • Cephalosporin active against gram negative bacilli may be used instead of an aminoglycoside • Cefotaxime, 50 mg/kg

20. INITIAL ANTIBIOTIC TREATMENTInfants and Children • Cephalosporin • Ceftriaxone, 100 mg/kg OR • Cefotaxime, 50 mg/kg • If unavailable: • Amoxicillin, 100 mg/kg AND • Chloramphenicol, 25 mg/kg

21. INITIAL ANTIBIOTIC TREATMENTADULTS • Cephalosporin • Ceftriaxone, 2 grams IV OR • Cefotaxime, 2 grams IV

22. INITIAL ANTIBIOTIC TREATMENTKnown or Suspected Pneumococcal Infection • Penicillin and cephalosporin resistance is possible • Vancomycin is the only antibiotic to which all strains of pneumococci are susceptible • Add Vancomycin, 15 mg/kg

23. CORTICOSTEROID TREATMENT • Dexamethasone, 0.15 mg/kg IV administered prior to or along with the initial antibiotics has been shown to decrease ICP, cerebral edema & CSF lactate. • Significantly decreases neurologic sequelae, including deafness

24. SEQUELAE • Mortality: 20-40% • Long-Term Sequelae: 20%